Which motor has the poorest speed control?

If I2 be the armature current, then speed of a D.C. shunt motor is_______________?

A. independent of Ia
B. proportional to la
C. varies as (Ia)
D. varies as la

For which of the following applications a D.C. motor is preferred over an A.C. motor ?

A. Low speed operation
B. High speed operation
C. Variable speed operation
D. Fixed speed operation

In a D.C. shunt motor, speed is______________?

A. independent of armature current
B. directly proportional to the armature current
C. proportional to the square of the current
D. inversely proportional to the armature current

Which of the following law/rule can he used to determine the direction of rotation of D.C. motor ?

A. Lenz’s law
B. Faraday’s law
C. Coloumb’s law
D. Fleming’s left-hand rule

For a D.C. shunt motor if the excitation is changed_______________?

A. torque will remain constant
B. torque will change but power will remain constant
C. torque and power both will change
D. torque, power and speed, all will change

Which of the following motor is preferred for operation in highly explosive atmosphere ?

A. Series motor
B. Shunt motor
C. Air motor
D. Battery operated motor